Glucose Homeostasis Flashcards
What are the 5 main hormones of glucose homeostasis?
Insulin
Glucagon
GH
Catecholamines
Cortisol
Where are insulin and glucagon produced?
Islets of Langerhans in pancreas
Where is GH produced?
Pituitary
Where are catecholamines produced?
Adrenal medulla
Where is cortisol produced?
Adrenal cortex
Which cells in islets of Langerhans release insulin and glucagon?
Glucagon - alpha cells
Insulin - beta cells
What types of molecules stimulate release of insulin?
Glucose
Amino acids
Fatty acids
Ketones
What are some beta cell agonists and how do they work?
Neurotransmitters and peptide hormones
Bind to beta cell receptors without entering the cell
Where does insulin independent glucose uptake occur?
-Neurons (GLUT3)
-Liver, RBC, intestine, pancreatic beta cells (GLUT2)
-RBC (GLUT1)
Where does insulin dependent glucose uptake occur?
-Muscle, adipose tissue (GLUT4)
-Pancreatic delta cells (GLUT4)
-GLUT4 is intracellular and its recruitment to the plasma membrane in insulin dependent
What are the effects of insulin on muscle cells?
-Glucose entry and glycogen synthesis
-Amino acid uptake and protein synthesis
-Ketone uptake
-Potassium uptake
What is the effect of insulin on adipose tissue?
Esterfication of glycerol-3-PO4 (hydroxyl group) with carboxylated acetyl Co-A leads to the formation of triglycerides (fat)
What state induces secretion of catecholamines through sympathetic stimulation?
Hypoglycemia
What do catecholamines do for glucose reg?
Break down glycogen into glucose in muscle during a fight or flight response. Done by glycogen phosphorylase
What is the Somogyi effect?
Overdose of insulin induces hypoglycemia, which induces catecholamine release and subsequent hyperglycemia. This gives the impression that the insulin dose is too low when really its too many slices
